Cu2O-BiOI isotype (p-p) heterojunction: Boosted visible-light-driven photoelectrochemical activity for non-enzymatic H2O2 sensing

A novel isotype (p-p) heterojunction, on the basis of Cu2O coupled with BiOI, has been designed and synthesized via a facile two-step electro-deposition approach at room temperature. The morphology, phase compositions and chemical bonding state were verified by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction measurements (XRD) and X-ray photoelectron spectra (XPS). The optimized Cu2O/BiOI hybrid electrode exhibited boosted photoelectrochemical (PEC) H2O2 non-enzymatic sensing performance under visible light illumination, with a phenomenally broad linear range (1.99 mu M similar to 17.54 mM), a high sensitivity of 213.87 mu A mM(-1) cm(-2), as well as a low detection limit of 0.44 mu M (S/N = 3). Additionally, the sensor presented satisfying selectivity, repeatability, stability and its feasibility in real samples was corroborated. The photoelectrochemical sensing mechanism was clarified in the view of band structure and p-p heterojunction. Our work would enlighten the perspective research on the application of isotype heterojunction in PEC bio-sensing and provide a promising non-enzymatic biosensor platform for effective detection of H2O2 in food, biomedical and environment analysis.